Splash guard for carburetor metering column



Jan. 29, 1963 ca. E. SELDON 3,075,748

SPLASH GUARD FOR CARBURETOR METERING COLUMN Filed Jan. 26. 1959 3,075,7d8 SPLASH GUARD FSR CARBURETGR METEPJNQ CQLUMN George E. Seidon, 534 N. Holmes Ava, Kirkwood, M0. Filed Jan. 26, 1959, er. No. 789,024 1 illaim. (ill. 261-75) This invention relates to a metering columns as used in my previous carburetor application No. 765,614, new U.S. Patent No. 2,996,789. The method of proportioning the rich mixture of air and fuel in the metering column of the auxiliary air circuit depends on unobstructed fuel and air passages for best operation. These carburetors are expected to operate on vehicles with rubber mounted engines which impart considerable motion to the solidly connected carburetor. Engine motion sloshes the fuel in the reservoir and causes violent waves on the free surface of the fuel in the pan. Since the air orifice is very close to the surface of the fuel, waves frequently strike the opening and interfere with the flow of air through the orifice into the column. This interrupts the proper mixing of air and fuel in the column and causes interruption of power flow fro-m the engine. It is objectionable to the occupants of the vehicle.

An object then of this invention is to provide a metering column that maintains a steady and continuous flow of rich fuel-air mixture.

It is an object of this invention to provide a metering column that flows the correct pre-determined fuel-air ratio without interruptions due to fuel slugs in the air orifice.

It is an object of this invention to provide a minimum cost metering column for a carburetor which will flow the correct fuel-air ratio without interruption.

FIG. 1 shows a section of the carburetor and the auxiliary circuit with the fuel port, air-bleed and splash protection guard.

FIG. 2 is substantially a section through the metering column at right angles to FIG. 1. It shows the metering column at the fuel-air inlet area.

In FIG. 1, the carburetor generally is indicated by 1. The primary air supply enters the carburetor at the airhorn 2, from which this air passes on to the narrow throat 3 of the venturi 4. The diffuser 5 then conducts this air onward to the throttle body 6; past the throttle plate 7 to the engine manifold 8, and finally to the engine 9.

The engine fi aspirates air past the throat 3 which is the narrowest part of the venturi air duct 4. Because the duct narrows here the air velocity is increased and the static pressure at the throat is reduced substantially the same amount as the increase in velocity head (or pressure) of the main air stream (Bernoulli). Orifices 10 are placed here. These orifices open into the auxiliary circuit 11, generally, and reduce the pressure in it, so that the ambient fluids of air and fuel tend to flow into this circuit. The fuel indicated generally by 12 is stored in the reservoir 23 from which the fuel 12 enters the auxiliary circuit at port 13. The ambient air pressure applied on the surface 14 of the stored fuel is able to lift the fuel surface in the tube 15 of the metering column 16 a distance it in homogenous fuel. This h represents a head or pressure equal to the velocity head or loss of static head in the venturi and at the orifices 10. However ambient air pressure also forces air into the metering column through air orifice 17. After passing orifice 17 and on entering the tube 15 this air meets the fuel at considerable velocity and mixes with it to form an emulsion 18 (a very rich mixture of fuel and air) which is much less dense than the undiluted fuel 12. This emulsion 18 rises rapidly in the tube 15 filling it and passing on through the metering orifice 19, passage 20, orifices 10, on through to the throat 3.

dfififidd Patented Jan. 29, 1%63 At the throat 3 the rich mixture of fuel and air originating in the metering column meets the main stream of primary undiluted air mixing with it to form a combustible mixture which then passes on past the throat 7 and through the manifold S to the engine 9.

The splash guard 21 is a cylindrical piece of material bored out on two diameters, the smaller inside diameter 22 just large enough to fit over the outside diameter of column 16. A larger diameter 24 concentric with 22 circumscribes the column. This diameter 24 is large enough to add substantially no friction to the air flowing through it toward the air orifice 17. The wall 25 of the splash guard is high enough to prevent substantially all fuel from splashing over it. The guard 21 is placed on the column 16 so that the small diameter 22 clears the air orifice 17 by at least the radius of the orifice. The guard may be soldered or brazed or otherwise permanently attached in this position. This splash guard then permits the air to enter the metering column through orifice 17 while preventing the fuel in the reservoir from entering the same orifice. For steady engine operation it is necessary that the flow of air and fuel be continuous throughout the auxiliary circuit and that the ratio of fuel to air remain unchanged even though the quantities fiowing may vary through a very Wide range. The splash guard is most effective to maintain proper metering column characteristics constantly. Splash guard 21 is sealed to lower end of tube or column 16.

FIGURE 2 shows a section through the reservoir 23 looking toward the venturi 4-. The reservoir 23 is of the mobile type and the fulcrum is indicated at 26. Reservoir is open to atmosphere substantially as shown and pivoted as shown in prior Patent No. 2,996,286. This mobile reservoir 23 is entirely adequate within its own structure to support and contain the fuel contents under any imposed loades in normal usage. It is selfcontained, and has no supports other than the fulcrums. The air inlet orifice 17 is also shown. The fuel enters the carburetor at the boss 27, flows down through tube 28 to the seat 29 and valve 313 which controls the flow into the reservoir. As shown here the valve 3% is on the seat 29 and there is no flow. However as the fuel is removed the reservoir turns clockwise on fulcrum 26 and the valve opens. Details of this action are explained in my previous application No. 765,614, now U.S. Patent No. 2,996,789.

In a vehicle the carburetor may be tilted or cornered making the surface 14 turn about the centerline of the column to plane 31. In this position the air orifice 17 is covered with liquid fuel. At low manifold depressions the air pressure outside the column can not remove the fuel from the front face of the orifice 17 and fuel only enters. Fuel-air mixing stops. However with guard 25' in place no fuel directly from outside the orifice is permitted to enter the column and mixing fuel and air proceeds normally. That is the guard permits normal operation even though the reservoir is banked. This is not possible with the column alone as shown in application No. 765,614, now U.S. Patent No. 2,996,789.

I claim:

In a vehicular carburetor having: a reservoir open at the top to the atmosphere and pivoted to said carburetor; said reservoir having a predetermined quantity of fuel; a venturi; a tube for adding fuel to said reservoir; an aspirating tube connected into said venturi, said aspirating tube having a fuel port submerged deep in the fuel in said reservoir, but spaced from the bottom thereof, said aspirating tube having also a metering a-ir port adjacent but just above the surface of said fuel, a tube like guard open at the top to the atmosphere, closed at the bottom, circumscribing said aspirating tube and sealed to the lower end of said aspirating tube, thereby forming an annular space between the guard and aspirating tube for 1 air entering from the top but into which space fuel may not enter directly from the reservoir, the lower part of said guard and space extending substantially below the surface of said fuel, said aspirating tube aspirating air and fuel as a very rich mixture from said reservoir and having means to deliver said mixture into said venturi, whereby air may flow through said metering air port into said aspirating tube while fuel from said reservoir is prevented from interfering with the steady flow of air through said air port.

References Cited in the file of this patent UNITED STATES PATENTS 

